Spirocyclic borate esters



United States Patent 3,256,310 SPIROCYCLIC BORATE ESTERS Theodor Weil, New Brunswick, N.J., assignor tov FMC Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Nov. 8, 1962, Ser. No. 236,442 12 Claims. (Cl. 260-462) This invention relates to the preparation of novel boron compounds, and, in particular, it relates to novel spi-rocyclic complex esters of boric acid.

Simple boric acid esters have not previously been found useful in industrial applications because of their ease of hydrolysis. Such hydrolysis-susceptible compounds could not be employed, for example, as agricultural fungicides or bactericides, where they canbe hydrolyzed by the soil moisture and completely destroyed in a short time.

I have discovered a novel class of hydrolytically stable spirocyclic boric acid complex esters containing tetracoordinated boron. These novel non-polymeric esters have the formula i OHz-CH-O o H2N B M CHz-CFH-O 0 wherein each Z is hydrogen or lower alkyl and M is a substituted ethylene or trirnethylene group or an aromatic ring connected in the ortho position.

Preferably, M is substituted as follows: when M is t 7\ R3 R4 R and R may each be hydrogen, alkyl, or aryl, R may be hydrogen, alkyl, aryl, or carboxyalkyl, and R may be hydrogen, alkyl, aryl, alkoxyalkyl, alkenyloxyalkyl, alkoxycarbonyl, aryloxyalkyl, or mercaptoalkyl: when M is the R radicals and R may each be hydrogen or alkyl, R may be hydrogen, alkyl, alkenyloxyalkyl, alkoxycarbonyl, alkoxyalkyl, alkanamido, or R and R may be joined in a single heterocyclic radical; and when M is the R radicals may each be hydrogen or lower alkyl.

I prepare my novel spirocyclic esters by reacting boric acid or boric anhydride with a 1,2- or 1,3-diol, and with a dialkanolamine in a liquid phase, preferably in the presence of an inert organic liquid. This condensation reaction is performed either by initially mixing all three of these reactants together and then heating the mixture to reaction temperature or by first reacting the boron com pound with either the amine or the alcohol separately, then adding the third reactant.

The reaction is conducted at .an elevated temperature and is continued until three moles of Water is formed for each mole of product. The water should be continually removed throughout the entire reaction. Upon completion of the reaction, the final product is separated from the liquid medium either as an oil, as a glass, or in the 5 form of crystals. If the amine-boric acid intermediate condensate is first prepared, it will not thereafter form esters by further reaction with a monohydric alcohol. I find that the alcohol reactant must be dihydric. Furthermore, I also find that a tertiary amine cannot be used to produce these spirocyclic esters, so that an N-alkyl dialkanolamine, for example, is totally unsuitable.

My reaction sequence can take the following course:

B-OH

Hai i wherein Z and M have the scope previously assigned.

The reaction sequence may be changed by adding the diol prior to the dialkanolamine or together with it.

Removal of the water can be performed in a number of different ways known to the art. A common method of reaction using an organic water-immiscible liquid carrier for the reaction. Suitable azeotrope-forming liquids include chloroform, hexane, heptane, benzene, toluene, Xylene, or other inert, organic liquid. The azeotrope mixture can be readily separated, for example, in a Dean- Stark apparatus, and the liquid carrier can be returned to the reaction vessel. The water may also be removed by azeotropic distillation using an organic Water-miscible liquid, such as sec-butanol. In this case, fresh liquid may have to be added during the reaction to replace that which is distilled off.

As stated above, either boric acid or boric anhydride may be employed as one of the reactants. Only half a mole of the anhydride is needed, as shown below:

EN mm:

CHa-C HOH water removal is by azeotropic distillation during the I I 3 Reaction of this cyclic intermediate with the diol will be the same as reaction (2) above.

Such dialkanolamines as diethanolamine and diisopropanolamine are suitable for this reaction. The only limitation on the selection of this reactant is that the nitrogen atom is not further substituted. As stated earlier, I have discovered that tertiary amines are unsatisfactory for the formation of my tetra-coordinated spirocyclic compounds. The alkanol segments, on the other hand, may be substituted by any radical which will not interfere withthe reaction. The preferred substituents are hydrogen and lower alkyl groups.

If the diol is reacted with boric acid or boric anhydride first, the intermediate will be HOB/ \M This intermediate is then reacted with the dialkanolamine. One mole of water is split off to form the corresponding complex ester.

According to this invention, acceptable diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 2,3-butanediol, 3- (o-tolyloxy)-1,2-propanediol, monoolein, 2,2-diethyl-1,3-propanediol, 2-buty1-2-ethyl- 1,3 -propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-dimethyl- 1,3-butanediol, 2,3-dimethyl-2,3-butanediol, 2-ethyl 1,3- hexanediol, benzopinacol, Z-methyl 2,4 pentanediol, 2- phenyl-oxazoline-4,4-dimethanol, 4-tert.-butyl pyrocatechol, 3-isopropyl-6-methyl-pyrocatechol, pyrocatechol, and dibutyl tartrate. This list should not be considered as a limitation on the number of diols which can be employed in this invention.

This condensation .reaction requires no special operating conditions to obtain quantitative yields, since the condensation products form quite readily. The reaction is preferably performed at'the reflux temperature of the organic liquid-water mixture, or if no liquid is used, then at the boiling point of water, at the operating pressure.

The following examples are illustrative of the invention.

EXAMPLE 1 A mixture of 30.9 grams (0.5 mole) of boric acid, 52.5 grams (0.5 mole) of diethanolamine and 200 ml. of toluene was added to a reaction flask equipped with a Dean-Stark apparatus, The mixture was heated to reflux and water of reaction began to form. When approximately 18 mls. of water was collected, 52 grams (0.5 mole) of neopentyl glycol was added and reflux was continued. Another 9 mls. of water separated out. The reaction mixture was cooled and crystallization was initiated by seeding. The crystals were washed in 200 ml. of ether, filtered and dried. A white crystalline product Was obtained with a yield of 93 grams (85.8% yield). The prodnot had a melting point of 125l26 C.

Analysis.Calcd. for C H O NB: C, 49.80; H, 9.29; N, 6.46; B, 4.99. Found: C, 49.70; H, 9.49; N, 6.39; B, 5.16.

EXAMPLE 2 Using the same apparatus as in Example 1,, 20.6 grams (0.33 mole) of boric acid, 35 grams (0.33 mole) of diethanolamine, and 55.4 grams (0.33 mole) of 4-tert.- butyl catechol in 200 ml. of toluene were mixed together. The reaction mixture was maintained at reflux temperature until 17 ml. of water had been collected in the trap. Upon crystallization and separation of the crystals, 91 grams (98.2% of theoretical) of a compound melting at 224-225 C. was obtained.

Analysis.Calcd. for C H O NB: C, 60.24; H, 7.81; N, 5.01; B, 3.88. Found: C, 60.46; H, 7.78.; N, 5.01; B, 3.76.

EXAMPLE 3 The procedure in Example 1 was changed slightly by reacting the diol with boric acid first. A mixture of 178.0 grams (0.5 mole) of monoolein, 30.9 grams (0.5 mole) of boric acid, and 300 ml. of toluene was refluxed as in Example 1. After 27 ml. of water had been collected in the Dean-Stark trap, 52.5 grams (0.5 mole) of diethanolamine was added. Reflux was continued until a further 7 ml. of Water had been collected. A homogeneous solution was obtained. The toluene was removed under reduced pressure at 90 C. whereupon a wax-like solid began to form.

Analysis.Cal-cd. for C H O NB: B, 2.30; N, 2.99; iodine No.: 51.81. Found: B, 2.40; N, 3.03; iodine No.: 54.07.

EXAMPLE 4 The following tables list various complex borate esters which have been prepared using two different dialkanolamines, diethanolamine and diisopropanolamine and a variety of diols. Analyses and melting points are included.

A. ESTERS PREPARED WITH DIETHANOLAMINE Diols Formula Melting Point, C.

Ethylene glycol 1,2-propanediol 3-mereapto-1,2-propan diol 2,3-butanediol Monoacetin. Pyrocateehol C 2methyloxazoline-4,4-dlmethanol 2methyl-2,4-pentanediol Pinacol Low melting glass 2,2,-dimethyl-1,3-butanediol 4. 81 3-methyl-2,4-pentanediol 97 4. 8 4. 90 2,2 diethyl-l,3-propanediol 9. 87 9. 91 74 4. 42 4. 67 2,2,4-trimethyl4,3-pentanedlol 10. 12 10. 27 5. 41 41 4. 18 4. 42 2ethyl-1,3-hexanedi01 orzHzeo NB 10. 11 10.02 5. 41 41 4. 18 4. 39 2-ethylg-zallyloxymethyl-l,3-pr0- C13H2GO5NB 9. 13 9. 56

pane 1o 2-butyl-2-ethyl-1,3-propanedlol C13Hg304NB 10. 34 l0. l4 5. 13 5. 31 3. 96 4. 09 3-IH9thyl-fi-iSODI'ODYlCfltBOhOl B 7. 95 7. 96 5. 01 4. 93 3. 88 3. 92 3-(o-tolyloxy)-1,2-pr0panediol. 56. 97 7. 52 7. 40 4. 75 4. 45 3. 67 3. 51 5-ethyl-3-methyl-2,4-heptanedi0l C 4HQ O4NB 58. 10. 53 10. 96 2-phenyloxazoline-4,4-dimethanoL O15H7405N2B 8. 75 7. 91 3 38 2 99 Monobenzal pentaerythritol CNHHOBNB Glass 56. 99 57. 01 7. l8 7. 31 Dibutyl tartrate CMIIMOBNB do 3. 74 4. 18 2. 89 2. 88 2-heptarainid0-2-methyl-1,3-pr0- CmHaaOfiNgB do 8. 14 8. 11 3. 15 3. 72

pane 1o 2-nonyloxazollne-4,4-dimethanol C1 H35O5NB 55. 9. 53 9. 60 7. 57 7. 52 Benzopinacol 030113004511; 82-83 75. 16 75. 44 6. 27 6.

B. ESTERS PREPARED WITH DIISOPROPANOLAMIN-E.

Melting C H N B Diols Formula P oilt,

. Cale. Found Calc. Found Cale. Found Cale. Found Ethylene glycol C3H1rO4NB 147-148 47.32 47. 79 8.94 9.54 Neopentyl glycol C 1H O NB. Glass 63.91 53:49' 9.81 9:79 Pyrocatechol 2H1304NB 90-92 57. 40 59. 03 7. 23 V 7. 92 S-iSOprOpyI-G-methy C1QH7BO4NB 130-133 62. 55 62. 36 8; 54 8. 69 4-tert.-butyl catechol CmHmO4NB 217-219 62.55 63.10- 8.54 8.-91

EXAMPLE 5 The compounds, as prepared by any of the above methods using the following amines and diols, were tested for fungicidaleffect on Aspergillus niger, Pullulatria pullulans, Penicillium expansum and Alternaria solzmi. These compounds were also tested :for eifectiveness in killing bacteria on Bacillus mycoides andAerobacter are'ogenes.

Item 13, the boric acidrester of diisopropanolamine and pyrocatechol GHQ-C H-O CHrC H-O I O 20 C Ha FUNGIOIDAL AND BACTERICIDAL TESTS OF BORIC ACID ESTERS PREPARED FROM DIFFERENT DI- ALKANOLAMINES AND DIOLS Compound Fungicidal Tests, mm. Bactericidal Tests, mm.

Dialkanolamme Dims niger pulfirma ezfisgitm. s i rii. myg o ides 1717,5221."

Neopentylglycol 5 a 4 5 s 7 2,3-butanediol 7 4 2 10 12 D0 -Pyrocatech01 5 5 2 9 8 Do 2,2-diethy1-1,3-propanedioL 2 6 7 5 5 5 Do .2-,ethyl-2-buty1-1,3-propanediol 6 9 4 12 6 10 Do 2,2,4-trimethyl-1,3-pentanediol. 9 8 4 15, 4 7

Do 2,2-dimethyl-1,3-butanediol 7 15 5 5 6' Do Pinacol 4 5 11 I 5' 6 7 Do 2-ethy1-1,3-hexanediol 15 14 15' 13 5 7 Do 2-methyl-2,4pentanediol 5 10 10 5 7 10 Diisopropanolamine NeopentylglycoL, 8 12 5 4' 7.5" 5

Diethanolamine 3-isopropyl-6-methyl catechol 10 20 8 2 Diisopropanolamine Pyrocatechol 12 17 10 14 10 Diethanolamine 3-tert.-butyl catechol 12 20 10 8 5 1 N 0 inhibition. 2 Complete inhibition.

Items 2, 9, 12, 13 and 14 in the immediately preceding table have the following structural formulae:

Item 14, theboric acid esterof diethanolamine and 3- tert.-butyl catechol Item 2, the boric acid ester of diethanolamine and 2,3- 0 butanediol CHa-CH-O CHz-CH;-O O-GHCH; H2N\ /B 11,1 1 1} CHg-CH-O CHz-CHz-O OCHOH (311F043;3

Item 9, the boric acid ester of diethanolamine and 2- (312E ethyl-1,3-hexanediol The above test results, showing the utility of these compounds, were obtained by placing. 0.25 gram of the test compound inside a ring of 1012 mm. (inside diameter) drawn in. the center of a plate containing fungus or bac- Item 12, the boric acid ester of diethanolamine and 3- isopropy1-6-methyl catechol teria cultures.

The fungus culture was incubated at 20 C. for 72 hours; the bacteria cult-ure'was incubated at 37C. [for 24-36 hours. After incubation, if a clear zone resulted, showingthat'the organism did not grow, the test compound was said to be toxic to the organism. The distance of that clear zone from the nearest culture growth to the center of the ring was measured and reported; for example, a non-toxic sample or a blank standard would have a measurement of zero or no inhibition, while a sample of extremely high toxicity would result in com plete inhibition.

an arylene groupof formula (c).

'The amino-boric acid intermediate has also been found to have activity as a bacte-ricide and fungicide. For example, the diethanolamine-boric acid cyclic compound was tested according to the above method with the following results;

' Mm. A. niger P. pullulans 10 Pen. expwnsum 12 Alt. solani 8. B. mycoides 12 A. aerogenes 13 These novel boric 'acid esters are stable to hydrolytic attack. They are generally water-soluble and may con veniently be applied industrially as a bactericid'e or fungioide in a water solution as well as in an inert organic solvent.

Having fully described my invention, I claim:

1. A spirocyclic borate ester of the formula in which Z is selected from the group consisting of hydrogen and lower alkyl and M is selected from the group consisting of (a) ethylene groups of the formula in which R and R are selected from the group consisting of hydrogen, alkyl, phenyl, R is selected from the group consisting of hydrogen, alkyl, phenyl, and carboxyalkyl, and R is selected from the group consisting of hydrogen, alkyl, phenyl, alkoxyalkyl, alkoxycarbonyl, I

aryloxyalkyl, and mercaptoalkyl,

(b) trimethylene groups of the formula A -C\ 2R5 R1 R5 R5 in which R and R are selected from the group consisting of hydrogen and alkyl, R; is selected from the group consistihg of hydrogen, alkyl, alkoxyalkyl, alkenyloxyalkyl, alkoxycarbonyl, and alkanamido, and

(c) arylene groups of the formula Rs in which R is selected from the group consisting of hydrogen and lower alkyl.

2. YA spirocyclic borate ester of claim 1 in which M is an ethylene group of formula (a). v

. 3. A spirocyclic borate ester of claim 1 in'which M is a trimethylene group of formula (b).

.4. A spirocyclic borate ester of claim 1 in which M is the formula 0-0 H0 H3 5. A vspirocyclic borate ester of Hal- 1 1 3 6. A spirocyclic borate ester of the formula CHT'CHg-O O-CH: Hil 1 n-orm CHrOH O o-r'armcm, 7. A spirocyclic borate ester of the formula 0 0H 0H 0 HzN /B CHrC rO \O/ CHaCHC Hz A spirocyclic borate ester of the formula (1H, 0 9. A spirocyclic borate ester of the formula in which Z is selected from the group consisting of hydrogen and lower alkyl, and (c) a'diol of the formula in which M is selected from the group consisting of (1) ethylene groups of the formula in which R and R are selected from the group consisting of hydrogen, alkyl, and phenyl, R is selected from the group consisting of hydrogen, alkyl, phenyl, and carboxyalkyl, and R is selected from the group consisting of hydro- .gen, alkyl, phenyl, alkoxyalkyl, alkoxycarbonyl,

aryloxyalkyl, and mercaptoalkyl,

(2) trimethylene groups of the formula in which R and R are selected from the group consisting of hydrogen and alkyl, R7 is selected from the group consisting of hydrogen, alkyl,

9 It) alkoxyalkyl, alkenyloxyalkyl, alkoxycarbonyl, in which Z is selected from the group consisting of and alkanamido, and hydrogen and lower alkyl, (3) arylene groups of the formula and removing water formed during the reaction.

RE 12. A method of preparing spirocyclic borate esters 5 which comprises heating a mixture of (a) a dialkanolamine of the formula i CH2CH-OH I HN s in which R is selected from the group consist- CH"(|3H OH ing of hydrogen and lower alkyl, Z and removmg Water formal dhhhg the f in which Z is selected from the group consisting of 11. A method of preparing spirocyclic 'borate esters hydrogen and lower alkyl, and Whlch corhpnses heatm'g a mlxture of (b) an organic boric acid condensation product of the (a) a drol of the formula formula HOB M HO in which M is selected from the group consisting of in which M is Selected f the group consisting f (1) ethylene groups of the formula (1) ethylene groups of the formula R1 R3 R1 BI 1 7 R3 R4 113 R4 in h f 1 and R3 Selected from the group in which R and R are selected from the group Fonslshng of hydrogen alkyl, f phenyl, R2 consisting of hydrogen, alkyl, and phenyl, R 15 Selected from the group cohslshhg of is selected from the group consisting of hydrogen, alkyl, phenyl, and CaYbQXYaIKYL and R4 gen, alkyl, phenyl, and carboxyalkyl, and R Selected from the group cohslshhg of hydrogen is selected from the group consisting of hydroialkylr phenyl, alkoxyalkylr alkoxycarbohyl, gen, alkyl, phenyl, alkoxyalkyl, alkoxycarbonyl, aryloxyalkyl, and mercaptoalkyl, aryloxyalkyl, and mercaptoalkyl, tflmflhylene groups of the formula (2) trimethylene groups of the formula R5 R5 R5 0 Ra C/ R0 C -;C \R7 C/ \R7 5 5 I 35 5 in which R and R are selected from the group in which R and R are selected from the group consisting of hydrogen and alkyl, R; is seconsisting of hydrogen and alkyl, R; is selected from the group consisting of hydrogen, lected from the group consisting of hydrogen, alkyl, alkoxyalkyl, alkenyloxy'alkyl, alkoxycaralkyl, alkoxyalkyl, alkenyloxyalkyl, alkoxybonyl, and alkanamido, and carbonyl, and alkanamido, and (3) arylene groups of the formula (3) arylene groups of the formula I R8 R8 p it. in

in which R is selected from the group conin which R is selected from the group consistsisting of hydrogen and lower alkyl, and I 1% of hydrogen and lqwer y (b) an organic boric acid condensation product of and removing Water formed dunng the Teactlonthe formula Z References Cited by the Examiner CHHIJH Lappert, Chem. Reviews, vol. 56, p. 978 (1956). 11,13 B-6 CHARLES B. PARKER, Primary Examiner.

CHr- -0 Y LEON D. ROSDOL, Examiner. 

1. A SPIROCYCLIC BORATE ESTER OF THE FORMULA 